Many Original Equipment Manufacturers (OEMs) have removed the dipsticks from their transmissions to save on cost and remove a potential source of water intrusion into the transmission. Due to this redesign, the process for checking the transmission fluid level on many of these transmissions can be complex and time consuming. In particular, transmissions today typically have an elevated drain tube in the transmission oil pan that will drain any excess transmission fluid above the intended fluid level. To determine if the fluid level is adequate in the transmission after a transmission or transmission component fix or replacement, or to check and/or refill the transmission fluid level after maintenance or monitoring, for example, a technician must first open the transmission drain plug. If there is an absence of draining transmission fluid upon opening the drain plug, transmission fluid is added through the refill port until the fluid fills the transmission oil pan above the level of the elevated drain tube. At that point, the transmission fluid will drain through the drain tube, allowing the technician to physically see, by way of the draining fluid, that the appropriate amount of transmission fluid is present in the transmission.
For the above method of determining the transmission fluid level to be most effective, and to maintain the safety of those inspecting the transmission, it is necessary that the transmission fluid be at or near a predetermined inspection temperature (e.g., 100° F.). The problem, from a technician's standpoint, for example, is that rarely vehicles requiring inspection and/or monitoring of the transmission fluid level are at the necessary temperature. Thus, long periods of time must be allocated to allow the transmission fluid to cool from an operating temperature of approximately 200° F. to the inspection temperature.
Transmission fluid levels are normally only checked due to a customer complaint about the operation of the vehicle, such as rough shifting, for example, which can often be the result of an improperly maintained transmission fluid level, whether too high or too low. However, when the customer takes their car into a service station for maintenance, the customer does not expect to be without their vehicle for several hours or more while waiting for the transmission fluid to cool to the required inspection temperature. A transmission level gauge and procedure are needed that will eliminate the downtime associated with waiting for the transmission fluid to cool. The present disclosure is directed to a transmission level gauge and methods for monitoring and/or replacing the transmission fluid in a transmission while the fluid is in an operating temperature range. The gauge is designed to prevent exposure of the technician to the hot transmission fluid, allowing for a safe and efficient means for checking and/or establishing the transmission fluid level in a transmission at operational temperatures.